Urban scholars across disciplinary boundaries have recently focused on the costs and benefits of gated communities on larger areas but the empirical evidence is quite limited. Using an original dataset, constructed specifically for the purpose of the study, this project integrates theories and methodologies from urban sociology and urban geography to understand the increasingly important socio-economic impact of gated communities on urban America. The authors juxtapose three theoretical frameworks, which lead to articulations of the gating process in different light: (1) the spatial assimilation approach (Massey and Mullan, 1984), (2) the place stratification approach (Alba and Logan, 1991) and (3) the theory of the club economy (Webster and Lai, 2003). The spatial assimilation approach and the place stratification approach are widely used in sociological research to understand the residential patterns of minorities and whites in the U.S. Applying these two perspectives to gated communities leads to the expectation that these communities most likely contribute to the patterns of segregation and separation in urban areas. The theory of the "club economy" suggests that gated communities are produced as territorial "club goods" in a similar fashion as private social clubs, which leads to the expectation that gated communities are mostly homogeneous enclaves. The juxtaposition of the theoretical perspectives guides us in addressing one central research question at two geographical levels: Do gated communities increase the levels of racial and economic residential segregation in urban regions? We examine this question by constructing dissimilarity and entropy indices at metropolitan level and then by applying spatial analysis of social distance at neighborhood level. We further apply hierarchical cluster analysis to test a typology of gated communities developed through our theoretical model. For the purposes of our analyses we construct a unique, comprehensive, geographically referenced dataset, encompassing 31 metropolitan areas. Thus far gated communities in the U.S. have been investigated with the methods of case studies, survey data or other types of data for specific urban areas. Therefore, at present we have only partial and conflicting knowledge about the socio-economic impact of gated communities on urban areas. The proposed research addresses this serious limitation in innovative data-gathering and analytical ways and the results will make several important contributions: (1) add to the academic debates related to gated communities, segregation and urban inequality;(2) be useful for policy makers at local, state and federal levels, who need to know more about the impact of gated enclaves;(3) be useful for non-governmental agencies and community organizations in defining their own agendas for neighborhood change.